stratified sample: meaning, definition, pronunciation and examples
C1Academic / Technical / Research
Quick answer
What does “stratified sample” mean?
A sample drawn from a population that has been divided into distinct subgroups (strata) based on specific characteristics, with individuals then randomly selected from each subgroup in proportion to its size in the population.
Audio
Pronunciation
Definition
Meaning and Definition
A sample drawn from a population that has been divided into distinct subgroups (strata) based on specific characteristics, with individuals then randomly selected from each subgroup in proportion to its size in the population.
In research methodology, a stratified sample ensures representation from all key subgroups within a population, improving accuracy and reducing sampling bias compared to simple random sampling. It is a cornerstone of rigorous survey design and statistical analysis.
Dialectal Variation
British vs American Usage
Differences
Usage is identical in meaning and application. Minor orthographic preferences may appear in surrounding text (e.g., 'behavioural' vs. 'behavioral stratification').
Connotations
Carries a strong connotation of methodological rigour and precision. It is a formal, technical term without casual equivalents.
Frequency
Equally frequent in academic and research contexts in both varieties.
Grammar
How to Use “stratified sample” in a Sentence
The researchers drew a stratified sample [of the population] [based on income brackets].A stratified sample [was obtained] [using postcode data].Vocabulary
Collocations
Examples
Examples of “stratified sample” in a Sentence
verb
British English
- The polling company will stratify the sample by constituency and voting history.
- We need to stratify before sampling to ensure regional balance.
American English
- The researchers stratified the sample by zip code and household income.
- Always stratify your data by the key demographic variables.
adverb
British English
- Participants were sampled stratifiedly across the four regions.
- (Note: 'Stratifiedly' is extremely rare; the adverbial concept is usually expressed with prepositional phrases like 'in a stratified manner').
American English
- The households were selected stratifiedly by income level. (Rare)
- The data was collected using a stratifiedly random process. (Rare)
adjective
British English
- The stratified sampling approach yielded more precise estimates.
- They published a paper on stratified sampling methodology.
American English
- A stratified sample design is essential for this study.
- The report detailed the stratified sampling procedure used.
Usage
Meaning in Context
Business
Used in market research to ensure a new product survey includes proportional feedback from different customer segments (e.g., by loyalty status or purchase frequency).
Academic
Fundamental in social science and medical research for obtaining generalisable results from a heterogeneous population.
Everyday
Virtually never used in casual conversation.
Technical
The precise process of dividing a sampling frame into strata and applying random sampling within each.
Vocabulary
Synonyms of “stratified sample”
Strong
Neutral
Weak
Vocabulary
Antonyms of “stratified sample”
Watch out
Common Mistakes When Using “stratified sample”
- Using 'stratified sample' to mean any non-random sample.
- Confusing it with 'cluster sample' (where intact groups are sampled).
- Misspelling as 'stratified sample'.
FAQ
Frequently Asked Questions
Not exactly. A stratified sample uses random selection *within* pre-defined subgroups (strata). It is a type of probability sample that incorporates both stratification (grouping) and randomness.
In stratified sampling, you divide the population into strata and sample from *all* strata. In cluster sampling, you divide the population into clusters, randomly select *some* clusters, and then sample (often all) individuals within those selected clusters.
Use it when your population has distinct, important subgroups (strata) and you want to ensure your sample accurately represents each subgroup's proportion in the population, or when you need precise estimates for each subgroup.
Technically, yes (e.g., quota sampling), but the term 'stratified sample' in rigorous methodology almost always implies random selection within strata. A 'stratified random sample' is the full, precise term.
A sample drawn from a population that has been divided into distinct subgroups (strata) based on specific characteristics, with individuals then randomly selected from each subgroup in proportion to its size in the population.
Stratified sample is usually academic / technical / research in register.
Stratified sample: in British English it is pronounced /ˈstræt.ɪ.faɪd ˈsɑːm.pəl/, and in American English it is pronounced /ˈstræt̬.ə.faɪd ˈsæm.pəl/. Tap the audio buttons above to hear it.
Phrases
Idioms & Phrases
- “None specific. The term itself is technical.”
Learning
Memory Aids
Mnemonic
Think of a layered cake (strata). To get a perfect taste of the whole cake, you need a slice that includes all layers in their correct proportions. A stratified sample is that 'perfect slice' of a population.
Conceptual Metaphor
SAMPLE IS A CROSS-SECTION / POPULATION IS A LAYERED STRUCTURE.
Practice
Quiz
What is the primary purpose of stratified sampling?